// Package _0_II__青蛙跳台阶问题 main
// @Title _0_II__青蛙跳台阶问题
// @Description
// @Author  == 琳琳也叫王木木 ==  2022-01-12 14:06
// @Create  2022-01-12 14:06
package main

import "fmt"

func numWays(n int) int {
	prev, curr := 1, 1
	for i := 2; i <= n; i++ {
		next := (prev + curr) % 1000000007
		prev = curr
		curr = next
	}
	return curr
}

func main() {
	fmt.Println(numWays(2))
	fmt.Println(numWays(3))
	fmt.Println(numWays(1))
	fmt.Println(numWays(0))
	fmt.Println(numWays(5))
}
